You are right it will be tail heavy. My herk will sit level on the mains w/the nose wheel retracted.

You might have to add nose weight. I needed 24 oz of lead in the nose and I also put a battery back in the nose.

The radome is the location with a bulkhead and bolt for removal.

I made a LARGE CG machine to check cg, Sorry I don't remember where I put the cg, but as I remember 25% of the main cord.

Mine might have been more tail heavy due to the 3 servos and receiver in the tail.

I put the rec. battery for the tail in the landing gear box.

The rec. battery for the wing is in the radome.

Use caution and check cg closely. Jim